A few weeks ago, a sharp-eyed coworker mentioned that he saw a rapid prototyper on Craigslist that I might be interested in. It turned out to be a Zcorp Z402C powder bed machine (a technology developed at MIT, which lays down complete powder layers and fuses them selectively rather than depositing material in a specific path like my Stratasys). The machine came with a depowdering station and a wax infusion machine, which are nice bonuses – not all used Zcorp machines come with them. The machine was residing at a high school (which was blessed with a very nice technology program) and was currently inoperable (though had been mechanically sound when put into storage some 3 years ago).

The Z402C has a powder supply on the left, which it wipes in a layer to the right (covered by the gantry) and then fuses the powder with an inkjet printer head inside the gantry. After each pass of the inkjet head, the supply is raised a little, the model bay is lowered a little, and a new layer of powder is spread.

Once the part has been printed and is carefully removed from the loose powder (which is basically plaster in this case), excess powder is dusted off in the depowdering station, which is essentially a fancy sandblast cabinet. Within the cabinet are a very nice air compressor and vacuum - no hardware store grade stuff here.

After depowdering the part, it is still quite fragile and needs to be strengthened. This can be done by dousing it with superglue, though this can warp the parts. An alternative is to use this nifty wax dipper, which dunks the part into a heated bath of paraffin for a selected time.

The seller said that they had diagnosed the problem to be a faulty motherboard (thankfully meaning a standard PC mobo, and not a custom proprietary PCB), and later, upon reviewing the photos I had taken when inspecting it, the issue jumped out at me:

Ho, ho! All that ails the motherboard are some blown capacitors. Getting this thing running seemed like a distinct possibility. Just one problem – I really didn’t need (or have space for) another rapid prototyper, much less a powder bed unit. But for a measly $500 for the whole system, I couldn’t just let it go. Fortunately, I managed to convince Frankie (not that it took much arm-twisting) that it would be a perfect addition to the technology lab that he’s setting up for the art school. Plus, much like with the Cole drill, I like knowing where I can put my hands on a particular tool, even if I have no use for it at the moment. So I told the seller to consider it purchased, and I’d be by in a week to take delivery.

After replacing the trailer hitch on the truck as well as the long-missing passenger side rear view mirror, I had a vehicle that met U-Haul’s rigorous requirements for trailer rental (in retrospect, I could have pulled up on a moped with a ball hitch and they still would have gladly taken my credit card). Loading the equipment onto the trailer was easy – being in a high school’s shop, there were plenty of kids to heave the stuff onto the trailer and strap it down. Once at Frankie’s studio that evening, we had notably less manpower at our disposal, but Frankie and I managed to manhandle all 3 pieces into the lab with no casualties. Charles dropped by later, and we all surveyed the bounty of the haul. We found the original machine invoices, and I forget what it all cost, but it was well over $50,000 when new. There were a few bottles of binder, a box of powder, documentation, little odds and ends… But we still had a dead machine. I took the motherboard and hard drive home to source replacement caps and image the hard drive (I recall reading somewhere that it’s a good idea to have a backup image of your Zcorp’s drive). Meanwhile, Frankie found the exact motherboard on Ebay as a refurbished unit, and bought it right away for about $175. Expensive, but when dealing with decade old PC equipment, it can be hard to find specific items. At any rate, we can always replace the caps on the original in the future if the refurb unit blows up someday.

The other week, we all met again at the studio to install the replacement motherboard and flip the power switch for the first time. I had wisely snapped a few photos of the cable connections before taking out the busted motherboard, so installing the new one and putting the drive back in place went quickly. Powering on the machine didn’t work, though – after about 20 minutes I found that I had plugged a ribbon cable in 2 pins off – after fixing this, the power button actually functioned (interestingly, the power button connects right to the pins on the PC motherboard, which remains in full control – I would have expected some other power/monitoring board to control the system at such a base level).

After that, we had a machine that was powered on, but not actually doing anything. We poked at it for a good long while, trying to coax it into doing the startup dance that the manual indicated it should be running (the video output that we hooked up really wasn’t of much help for anyone who wasn’t a trained Zcorp technician, but it did seem to indicate that the machine was at least reading some encoder feedback). After much web searching, Frankie tried jumpering some photosensors to bypass them, and suddenly the machine began to move the gantry of its own accord. Victory!

We still didn’t have a null modem serial cable to communicate to the Zcorp with (needed to actually download files to it for printing), so we called it a night, pleased that we had resurrected the beast. This past weekend, Frankie managed to scrounge up the needed cable and set the machine running a few layers. It still needs calibration, the water cleaning the binder lines needs to be flushed through, and the screws and shafts could use a bit of cleaning and lubrication, but it’s a very healthy start to what I hope will be a great machine for the lab.

Excellent find. Is there a way to send you an email? I remember chatting previously on the makergear IRC channel. I have an idea for a 3D printing event here in Milwaukee and wanted to communicate about the possibilities.

Hi, I wonder if you could help me. There is a none working Z406 for sale that says
‘The not so good bits
The problems I have seen are: 1) intermittent errors with the print heads which may be solved by simply replacing them, they are standard HP cartridges. 2) an issue with the binder flow pressure which results in no flow and will require bleeding the line. Other than the above, everything else including power now appears to be working correctly.’

Do you think this is an easy fix? I’m quite handy with tech stuff but my main concern is if I need any spares, I’m sure that they would be expensive or hard to get.

The print heads do have a limited lifespan, and users will generally hack Canon cartridges with fittings to convert them for use. The binder flow pressure sounds like there could be a clog in the line somewhere and doing a full system flush might be a good idea. I’d try contacting Chris Meyer at Sector67 (http://www.sector67.org/) – He knows a great deal about the Zcorp machines and may be able to give some insight.

cheers, thanks for that. I enquired on a UK website for consumables, next day I got a call from them. They rubbished the 406 saying it was old and not upto the quality of a 650, then tried to sell me a new one! DO I LOOK LIKE I’M MADE OF MONEY!

I’m not surprised – whenever I mention to a Stratasys dealer that I have an old FDM, they immediately tell me that I should trade it in for the late$t model. I’ll keep using my old non-crippled machine, thank you very much.

Patch! I need help with this 400, its been dormant a cpl months…what are the steps to bring it back to life? It turns on zeroes the gantry then alerts the alert and ready ‘binder tank not filling’ help pleaseee. I cant find help anywhere! I might end up just sellin it for the right price. Still looks good and ran 2 mo ago…i feel like its a fixable problem

Hey HaveBlue, did this machine happen to come with software? Software for the 402c (color) models is non existant, and using the standard zprint software only lets you print in monocrome. Theirs a bunch of people on the 402 user group that would kill for this http://finance.groups.yahoo.com/group/zcorp402/

Yep, there was some software that came with it, but as it’s from 2000 or so, I’m not sure how much people would want it! I didn’t know that using the zPrint software only allows monochrome – as far as I know, Frankie hasn’t tried getting it to print in color yet (he’s been happy to just run it with binder, not even any dye).

Hi HaveBlue, I’d seen over on the zcorp402 Yahoo group that you might have the color print software (which, as Zak said, isn’t the standard zPrint). Would you be willing to share a copy of that software? I just got a used 402C, but it only came with a copy of the standard zPrint software.

Hi Have Blue!
I too just bought a used 402 and the disk that came with it says it cant run on my windows 8 pc, even in compatibilty mode. May I also try that so try that color software for the zcorp z402?

We just revived a Z406 in our Physical Computing lab at University, but we miss the materials to make it work, and actually, have no clue of what we should use, as they discontinued the original materials. Does anyone have a direction to show us?

I’m trying to contact the support but i’m not sure if they’ll help us..they will most probably say “get a newer one” LOL

“Get a newer one” won’t make you any happier, I’m afraid – a friend uses a leased new model zCorp at his workplace, and it’s been very problematic, despite being fully supported, maintained, etc. They can’t wait for the lease to end so they can send it back and get something else.

I just heard of this company the other day, and it looks like they have a full selection of materials: Noble 3D Printers

You should also be able to do DIY mixes – I recall one blog detailed using rice flour and sake as powder and binder!

If you’re new to 3D printers, I’d probably shy away from the zCorp machines, unless you really enjoy tinkering. They’re not bad, but they do seem to be temperamental. A friend’s company runs a current 3DS machine, and they can’t wait for the lease to run out so they can get rid of it – even with multiple service technician visits, it’s still a nightmare to keep operational.

Man that’s crazy. I just acquired a z400 from an auction by a local university. Kinda similar situation except mine powered on no problem, read throw a few pagee of commands zeroes the gantry and homes itself but after tht thw faithful error noise starts, the error light blinks in the sec interv and the msg ‘binder tank not filling, press feed to continue anyway’ show up in thw next line….how do you get to that next step? And how do i get the software from a home computer to the z400?

Also, im interested in selling the above mentioned z400 for the right price. As stated it came from a university, normal wear, still looking good. Local pickup is encouraged…it weighs 300lbs (Atl GA) jpgantt78@gmail.com for pics